Note: With some versions of Firefox, the data files are not backward compatible. If there is an issue, create a new profile and we can tell you how to recover the data. Step one: How do you completely turn off update checks in Firefox v64? You can use a policies.json file to disable updates for all users. https://github.com/mozilla/policy-templates/blob/master/README.md or https://winaero.com/blog/disable-updates-firefox-63-above/ You can use a policies.json file in the distribution folder in the Firefox installation folder instead as also listed in the article, so no need to use GPO keys in the Windows Registry. • https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ You can use the ManualAppUpdateOnly policy in Firefox 87+ to enable only manual updates e.g. via "Help -> About Firefox". * https://github.com/mozilla/policy-templates#manualappupdateonly * https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson Note that it is important to stay up to date and install the latest security patches. * https://www.mozilla.org/security/known-vulnerabilities/firefox.html